Optical member, image pickup apparatus, and method for manufacturing optical member

Abstract

To provide an optical member in which crystallization is suppressed and which has a porous glass layer on a base material. An optical member has a base material 1 and a porous glass layer 2 which is formed on the base material 1 and has a three-dimensional through pore, in which the existence ratio of crystals of 0.2 micrometer or more in the porous glass layer 2 is 1.0% or lower.

1 . An optical member comprising:
 a base material; and   a porous glass layer which is formed on the base material and has a three-dimensional through pore,   an existence ratio of crystals of 0.2 micrometer or more in the porous glass layer being 1.0% or lower.   
     
     
         2 . The optical member according to  claim 1 , wherein the existence ratio of the crystals of 0.2 micrometer or more in the porous glass layer is 0.35% or lower. 
     
     
         3 . The optical member according to  claim 1 , wherein a pore diameter of the porous glass layer is 5 nm or more and 50 nm or lower. 
     
     
         4 . An image pickup apparatus comprising: the optical member according to  claim 1 ; and an image pickup device which captures an image which transmits the optical member. 
     
     
         5 . The image pickup apparatus according to  claim 4 , wherein, in the optical member, the base material and the porous glass layer are disposed in the stated order from the image pickup device side. 
     
     
         6 . A method for manufacturing an optical member having a base material and a porous glass layer formed on the base material, the method comprising:
 forming a glass powder layer containing a plurality of glass powders on the base material;   fusing the plurality of glass powders of the glass powder layer to form a base glass layer;   phase separating the base glass layer to form a phase-separated glass layer; and   etching the phase-separated glass layer to form a porous glass layer, the formation of the base glass layer including heating the glass powder layer at a temperature elevation rate of 50 degree(Celsius)/min or higher to a temperature equal to or higher than a crystallization temperature of the glass powder and equal to or lower than 1200 degree(Celsius).   
     
     
         7 . The method for manufacturing an optical member according to  claim 6 , wherein the formation of the base glass layer includes heating the glass powder layer at a temperature elevation rate of 200 degree(Celsius)/min or higher to a temperature equal to or higher than the crystallization temperature of the glass powder and equal to or lower than 1200 degree(Celsius). 
     
     
         8 . The method for manufacturing an optical member according to  claim 6 , wherein the formation of the base glass layer includes heating at a temperature of the glass powder equal to or higher than a crystallization temperature and equal to or lower than 1200 degree(Celsius) for a heating time of 5 minutes or more and 20 hours or lower. 
     
     
         9 . The method for manufacturing an optical member according to  claim 6 , wherein the base glass layer contains silicon and aluminum. 
     
     
         10 . The method for manufacturing an optical member according to  claim 9 , wherein an aluminum to silicon ratio in the base glass layer is 0.005 or more and 0.090 or lower.